Worst ISP with staff that do not even return calls and escalations

This is the worst ISP I have ever dealt with, I cancelled my Service with them due to bad service and they never made arrangement to collect their route. After about 8 calls and now responses to my messages to them they eventually picked it up. They trying to Claim a Claw back from me and when I inquiry to what is the claw back is for they can not tell me. Now they have handed me to a debt recovery agency even after they are failing to assist me with the enquires